The useful life of a medical device depends on its initial quality. Let X denote the useful life of the device imeasured in weeks), and let Y denote the initial quality of the device. The device is such that its initial quality is in one of three classifications. These classifications are denoted by 1, 2, and 3 where 1 is best and 3 is worst. Let fy denote the PMF of where FD=09 F=007 fH=003 Furthermore, suppose E(x|r=1)=250 E(x|y=2]=120 E(X|y=3)=30 and StDev| X|Y =1)= 30 StDev( X| =2]=40 \f